Featured Research

from universities, journals, and other organizations

Late Treatment With Letrozole Can Reduce Breast Cancer Recurrence Risk

Date:
March 13, 2008
Source:
Massachusetts General Hospital
Summary:
Treatment with the aromatase inhibitor letrozole can reduce the risk of breast cancer recurrence even when initiated one to seven years after a course of tamoxifen therapy. Among women originally in the placebo arm of an international trial of letrozole who chose to begin letrozole treatment after the initial trial was halted, the risk that their cancer would recur was cut in half compared with those who never received letrozole.

Treatment with the aromatase inhibitor letrozole (Femara) can reduce the risk of breast cancer recurrence even when initiated one to seven years after a course of tamoxifen therapy. The results of a study involving women originally in the placebo arm of an international trial of letrozole will appear in the Journal of Clinical Oncology and are receiving early online release. Among those who chose to begin letrozole treatment after the initial trial was halted, the risk that their cancer would recur was cut in half compared with those who never received letrozole. In addition, the risk of metastasis was 60 percent lower with letrozole, and the chance that a new tumor would develop in the unaffected breast dropped more than 80 percent.

Related Articles


"It appears that estrogen-sensitive tumors remain hormone dependent and that patients' survival can be improved with careful use of aromatase inhibitors, even many years after completing tamoxifen treatment," says Paul E. Goss, MD, PhD, director of Breast Cancer Research at Massachusetts General Hospital Cancer Center, who led both the current study and the earlier investigation, called the MA.17 trial. "These results can be put into practice right away to improve the outlook for women treated for receptor-positive breast cancer."

Letrozole is one of a class of drugs called aromatase inhibitors that suppress the production of estrogen, which stimulates the growth of breast tumors expressing the estrogen receptor. The most widely used estrogen-blocking drug is tamoxifen, but the benefits of tamoxifen treatment drop significantly after five years, while the drugs' side effects continue.

The original MA.17 trial, conducted through the National Cancer Institute of Canada, was designed to test whether letrozole could reduce tumor recurrence and increase survival in breast cancer patients who had completed five years of tamoxifen treatment. The study was halted in October 2003 -- a year earlier than planned -- when interim data analysis showed that tumors of women taking letrozole were significantly less likely to recur. The final analysis of MA.17 data, published in the September 7, 2005 Journal of the National Cancer Institute, confirmed that women taking letrozole had significantly better disease-free survival than those taking a placebo.

Since women who received letrozole in the MA.17 trial began taking the drug within a few months of stopping tamoxifen treatment, letrozole's current approval restricts the initiation of therapy to the first three months after tamoxifen discontinuation. However, participants in the placebo arm of the MA.17 trial were offered the opportunity to begin letrozole treatment when that trial was halted, which gave investigators the opportunity to determine whether those women could also benefit from the drug.

The current study analyzes data on more than 1,500 women from the placebo group who chose to take letrozole and about 800 who chose no further treatment. Almost three years after the MA.17 trial was halted and letrozole offered, those who began letrozole therapy had only a 2 percent risk of tumor recurrence, compared with almost 5 percent in those choosing no treatment. The risk of death from breast cancer during that period was cut in half in those receiving letrozole. Treatment also reduced the risk of metastasis by 61 percent and appeared to prevent development of a new tumor in the opposite breast by 82 percent.

The research team notes that this study is limited by the fact that participants choose whether to take the drug themselves and were not randomly assigned. While a randomized clinical trial would more conclusively determine the benefit of letrozole treatment for those who have been off tamoxifen for several months or years -- or even those who never took the drug -- the results of this study can help guide physicians and patients in deciding whether letrozole therapy would be appropriate.

"Every patient who has previously taken tamoxifen should discuss these new results with her oncologist. The risk that hormone-dependent breast cancer will recur continues indefinitely, and our results imply that aromatase inhibition is effective whenever initiated," says Goss, a professor of Medicine at Harvard Medical School

The current study was supported by grants from the Canadian Cancer Society, the National Cancer Institute of Canada, the U.S. National Cancer Institute and Pharmacia Corp. Novartis Pharmaceuticals, which markets letrozole under the brand name Femara, also supported and provided study medications for the initial MA.17 trial and the current study.

Co-authors of the JCO study are James Ingle, MD, Mayo Clinic; Silvana Martino, DO, Angeles Clinic and Research Center; Nicholas Robert, MD, Inova Fairfax Hospital, Falls Church, Virginia; Hyman Muss, MD, University of Vermont; Martine Piccart, MD, Institut Jules Bordet, Brussels; Monica Castiglione, MD, University of Bern; Dongsheng Tu, PhD, Lois Shepherd, MD, Michael Palmer, MSc, and Joseph Pater, MD, National Cancer Institute of Canada Clinical Trials Group; Kathleen Pritchard, MD, Toronto-Sunnybrook Regional Cancer Centre; Robert Livingston, MD, University of Washington; Nancy Davidson, MD, Johns Hopkins Hospital; Larry Norton, MD, Memorial Sloan-Kettering Cancer Center; Edith Perez, MD, Mayo Clinic, Florida; Jeffrey Abrams, MD, National Cancer Institute; and David Cameron, MD, Western General Hospital, Edinburgh.


Story Source:

The above story is based on materials provided by Massachusetts General Hospital. Note: Materials may be edited for content and length.


Cite This Page:

Massachusetts General Hospital. "Late Treatment With Letrozole Can Reduce Breast Cancer Recurrence Risk." ScienceDaily. ScienceDaily, 13 March 2008. <www.sciencedaily.com/releases/2008/03/080310181556.htm>.
Massachusetts General Hospital. (2008, March 13). Late Treatment With Letrozole Can Reduce Breast Cancer Recurrence Risk. ScienceDaily. Retrieved November 22, 2014 from www.sciencedaily.com/releases/2008/03/080310181556.htm
Massachusetts General Hospital. "Late Treatment With Letrozole Can Reduce Breast Cancer Recurrence Risk." ScienceDaily. www.sciencedaily.com/releases/2008/03/080310181556.htm (accessed November 22, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Saturday, November 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

WFP: Ebola Risks Heightened Among Women Throughout Africa

WFP: Ebola Risks Heightened Among Women Throughout Africa

AFP (Nov. 21, 2014) Having children has always been a frightening prospect in Sierra Leone, the world's most dangerous place to give birth, but Ebola has presented an alarming new threat for expectant mothers. Duration: 00:37 Video provided by AFP
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com
Milestone Birthdays Can Bring Existential Crisis, Study Says

Milestone Birthdays Can Bring Existential Crisis, Study Says

Newsy (Nov. 21, 2014) Researchers find that as people approach new decades in their lives they make bigger life decisions. Video provided by Newsy
Powered by NewsLook.com
Ebola: Life Without School in Guinea

Ebola: Life Without School in Guinea

AFP (Nov. 21, 2014) Following the closure of schools and universities in Guinea because of the Ebola virus, students look for temporary work or gather in makeshift classrooms to catch up on their syllabus. Duration: 02:14 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins